<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
<style>


.mg {overflow:hidden; }
.rowone { background:#f00; height:100px; margin-bottom:100px;}
.rowtow { background:#090; height:100px; margin-top:100px; }
</style>
</head>

<body>

    <div class="rowone">
    </div>

<!--
外面那层 overflow:hidden; 会触发bfc;
注意: overflow:hidden只是会给容器里的元素生成BFC,不影响本元素所在的bfc
-->
<div class="mg">
  <div class="rowtow">
  </div>
</div>



</body>
</html>
